A Mesoporous, Silica‐Immobilized‐Nanoparticle Colorimetric Chemosensor for the Detection of Nerve Agents

Abstract

A new and an easy‐to‐make colorimetric azo‐pyridine, 1, and its recyclable mesoporous silica‐immobilized nanoparticles for nerve‐agent detection are synthesized. The binding site, comprising an azo‐pyridine moiety, is capable of selectively sensing diethylchlorophosphate (DCP), one of the nerve‐agent mimics of chemical‐warfare agents, over a series of other phosphate compounds. Compound 1 shows ratiometric changes in absorption spectroscopy to the extent of a 60 nm red‐shift upon the addition of DCP, mainly due to a change in the intramolecular charge transfer (ICT) in 1. The color change of receptor 1 from yellow to red in the concentration region ≈1.0 × 10−6 M is sufficient for the selective detection of the DCP nerve‐agent mimic by the naked eye. With regards to solid‐phase application, mesoporous silica nanoparticles using 1 (MSIAP) are also prepared using a sol‐gel grafting reaction. The color of the MSIAP also changes from red to yellow when dipped into an aqueous DCP solution, and turns back to red when treated with NaOH solution, with nontoxic diethylphosphoric acid being given off. The absorption changes of MSIAP in the presence of DCP are consistent within the 3–9 pH range.

Supramolecular Detection of a Nerve Agent Simulant by Fluorescent Zn–Salen Oligomer Receptors

“…To date, only a few examples of supramolecular hosts for CWA simulants have been reported in the literature [14,15,16,17,18,19,20,21,22,23,24]. They exploit several non-covalent interactions for the recognition of the guest, such as inclusion within the hydrophobic macrocyclic cavity [14,15,16,17] or hydrogen bond-dependent gel formation [18,19,20,21,22,23,24,25].…”

“…They exploit several non-covalent interactions for the recognition of the guest, such as inclusion within the hydrophobic macrocyclic cavity [14,15,16,17] or hydrogen bond-dependent gel formation [18,19,20,21,22,23,24,25]. …”

Nerve Gas Simulant Sensing by a Uranyl–Salen Monolayer Covalently Anchored on Quartz Substrates

“…[39][40][41][42][43][44] Recently,anew method consisting of surface-enhanced Ramans cattering measurements after watere vaporation and am ore concentratedsolutiono fD MMP wasr eported. [39][40][41][42][43][44] Recently,anew method consisting of surface-enhanced Ramans cattering measurements after watere vaporation and am ore concentratedsolutiono fD MMP wasr eported.…”

“…Therefore, some sensors for CWAs involvet he formationo f ac ovalentb ond between an ucleophilic group of the sensor and the reactive P=Og roup. [39][40][41][42][43][44] Recently,anew method consisting of surface-enhanced Ramans cattering measurements after watere vaporation and am ore concentratedsolutiono fD MMP wasr eported. [45] Also, attenuated total reflectance (ATR) IR spectroscopy has been applied to as tudy of the interactions of DMMP with amorphous a-SiO 2 grown by plasma oxidation of Si, on Al 2 O 3 , and on AlOÀ(OH) surfaces as af unction of the relative humidity.…”

Sensitive fluorescence on-off probes for the fast detection of a chemical warfare agent mimic

“…Likewise, many of these problems can be overcome using optical sensors and notably fluorescence probes are emerging as suitable alternatives due to their ease of handling, low cost and high sensitivity [16][17][18][19][20][21].…”